Hand spinning will get it up to speed. Once up to speed, the load on the belt/motor should be the same with or without the weight (physics). If it is different, then you have something dragging or a bad bearing that results in extra frictional force exacerbated by the weight.
Turntable weight affects speed
I tried a Thorens tt weight on my Thorens TD-850 belt-drive tt. It noticeably slowed it down. It seems like extra weight on the bearing would affect any tt, but what do I know? Is a speed control (and strobe/test pattern) generally required to use a turntable weight while maintaining the proper speed?
Showing 4 responses by carlsbad2
@clearthinker I'm done. best of luck. |
@jea48 good theory. something is rubbing that shouldn't be rubbing, and with the extra mass, it rubs more. |
@clearthinker Please understand that my post here is meant to keep the physics correct and not to embarass you. You have a rudimentary understanding of some physics concepts, just enough to be dangerous, as they say. Indeed, there is angular momentum, which is constant and once accelerted to speed, needs no force to maintain it. It is the acceleration that is different with mass (as I explained). As others have said, belt drives can struggle accelerating to speed, which is why many spin by hand before turning on. Once spinning all the motor has to overcome is the friction of the stylus, the load of the bearing (very low with a precision high end turntable) and losses in the belt and the motor. None of these change with mass. Some might think friction increases with mass. Indeed it does when sliding a mass on an inclined plane for a high school physics problem. But with a precision bearing, there should be negligable difference with the mass added. The exception I mentioned earlier would be a bad bearing that has more resistance to rotation with the increased mass. Jerry |